Television viewing and time spent sedentary in relation to cancer risk: A meta-analysis (#1184)

Sedentary behavior has been suggested to represent
a risk factor for chronic morbidity and mortality. The relation of television
(TV) viewing to cancer risk has not been quantitatively summarized using
meta-analysis.

Aim:

We aimed to quantify the relations of TV viewing time, recreational sitting time, occupational sitting time, and total sitting time to the incidence of any type of cancer.

Methods:

We searched Cochrane, EMBASE, Medline, and
SciSearch data-bases through February 2014 for published articles exploring TV
viewing and other sedentary behaviors in relation to cancer incidence. The
meta-analysis was conducted according to the Preferred Reporting Items for
Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Relevant studies were
summarized using random-effects meta-analysis and meta-regression.

Results:

We included information from 43 observational
studies and 68 936 cancer cases in our meta-analysis. High versus low levels of
TV viewing time were related to a significant increased risk of colon cancer
(Relative risk [RR]=1.54; 95% confidence interval [CI]=1.19 to 1.98) and
endometrial cancer (RR=1.66; 95% CI=1.21 to 2.28). Further, increased
occupational sitting time was associated with an elevated risk of colon cancer
(RR=1.24; 95% CI=1.09 to 1.41). For total sitting time, the RRs were 1.24 (95% CI=1.03
to 1.50) for colon cancer, 1.32 (95% CI=1.08 to 1.61) for endometrial cancer,
and 1.21 (95% CI=1.03 to 1.43) for lung cancer. By comparison, sedentary
behavior was unrelated to cancers of the breast, rectum, ovaries, prostate,
stomach, esophagus, testes, renal cell, and non-Hodgkin lymphoma.

Conclusions:

According to our meta-analysis of observational
epidemiologic studies, prolonged TV viewing and time spent in other sedentary behaviors
represents a risk factor for the development of certain types of cancer.